1,716 research outputs found

    Flavonoid Distribution in Asplenioid Ferns

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    In a survey of 15 representatives of the Asplenioid ferns for the pinnae flavonoids, kaempferol was found in 80 %, quercetin 53% and proanthocyanidin 13% of the species studied. Kaempferol3 O-methyl ether was found in A. marinum only. Acacetin and genkwanin have been previously found in the fern, Notholaena bryopoda (Polypodiaceae), but for the first time in A. normale. This is the second report of the occurrence of this type off lavoneinferns. Hispidulin and pectolinangenin were detected inA. glaucophyllum in trace amounts due to the small sample and at a relatively low concentration. Scutellarein was detected inA. belangeri. To our knowledge, this is the first report of the existence of hispidulin, pectolinangenin and scutellrein in ferns

    A critical assessment of data derived from coral cay conservation volunteers

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    Since 1986, Coral Cay Conservation (CCC) has utilized a workforce of over 900 specially-trained volunteer divers to collect detailed topographic, bathymetric and biological data for the establishment of management plans for selected areas of the Belize barrier reef. The biological data recorded are ordinal and reflect the abundance of reef organisms including fish, macroalgae and hermatypic corals on a scale of 0-5. Substrate composition and the coverage of principal biotic classes are also visually assessed using an ordinal scale of 0-5. An exercise was carried out to assess the accuracy and consistency of data recorded by volunteers. Transects were laid in each of the major reef zones and in lagoon habitats. Each transect was surveyed independently by six teams of trained volunteers and compared to a reference obtained by experienced CCC staff. Analyses were carried out to test the accuracy and consistency of the coral, macroalgal and habitat data. Further analyses sought to quantify the proportion of species correctly identified, the frequency of erroneous species recordings and the variation of abundance ratings. The overall accuracy of coral surveys varied from 52-70% with the poorer values obtained in deeper outer and inner drop-off reef zones. The trend of reduced surveyor performance in deeper water is discussed in terms of physical, physiological and psychological phenomena. Inter-group consistency exhibited a similar bathymetric trend to that found for coral accuracy. Macroalgae were generally accurately and consistently recorded. No clear trend of improved accuracy and consistency following greater survey experience was apparent. Substrate composition and biological cover were recorded with an accuracy exceeding 90% in seagrass habitats and 70-90% in reef sites. A number of recommendations are made to improve survey methodology and volunteer training

    Marine Reserves Enhance the Recovery of Corals on Caribbean Reefs

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    The fisheries and biodiversity benefits of marine reserves are widely recognised but there is mounting interest in exploiting the importance of herbivorous fishes as a tool to help ecosystems recover from climate change impacts. This approach might be particularly suitable for coral reefs, which are acutely threatened by climate change, yet the trophic cascades generated by reserves are strong enough that they might theoretically enhance the rate of coral recovery after disturbance. However, evidence for reserves facilitating coral recovery has been lacking. Here we investigate whether reductions in macroalgal cover, caused by recovery of herbivorous parrotfishes within a reserve, have resulted in a faster rate of coral recovery than in areas subject to fishing. Surveys of ten sites inside and outside a Bahamian marine reserve over a 2.5-year period demonstrated that increases in coral cover, including adjustments for the initial size-distribution of corals, were significantly higher at reserve sites than those in non-reserve sites. Furthermore, macroalgal cover was significantly negatively correlated with the change in total coral cover over time. Recovery rates of individual species were generally consistent with small-scale manipulations on coral-macroalgal interactions, but also revealed differences that demonstrate the difficulties of translating experiments across spatial scales. Size-frequency data indicated that species which were particularly affected by high abundances of macroalgae outside the reserve had a population bottleneck restricting the supply of smaller corals to larger size classes. Importantly, because coral cover increased from a heavily degraded state, and recovery from such states has not previously been described, similar or better outcomes should be expected for many reefs in the region. Reducing herbivore exploitation as part of an ecosystem-based management strategy for coral reefs appears to be justified

    Uniting paradigms of connectivity in marine ecology

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    The connectivity of marine organisms among habitat patches has been dominated by two independent paradigms with distinct conservation strategies. One paradigm is the dispersal of larvae on ocean currents, which suggests networks of marine reserves. The other is the demersal migration of animals from nursery to adult habitats, requiring the conservation of connected ecosystem corridors. Here, we suggest that a common driver, wave exposure, links larval and demersal connectivity across the seascape. To study the effect of linked connectivities on fish abundance at reefs, we parameterize a demographic model for The Bahamas seascape using maps of habitats, empirically forced models of wave exposure and spatially realistic three-dimensional hydrological models of larval dispersal. The integrated empirical-modeling approach enabled us to study linked connectivity on a scale not currently possible by purely empirical studies. We find sheltered environments not only provide greater nursery habitat for juvenile fish but larvae spawned on adjacent reefs have higher retention, thereby creating a synergistic increase in fish abundance. Uniting connectivity paradigms to consider all life stages simultaneously can help explain the evolution of nursery habitat use and simplifies conservation advice: Reserves in sheltered environments have desirable characteristics for biodiversity conservation and can support local fisheries through adult spillover

    Flavonoid Glycosides from the Pinnae of Lunathyriumjaponicum

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    ABSTRAK Penyelidikan semula terhadapflavonoid glikosida dart spesies L.japonicum telah menunjukkan kehadiran kuersetin 3-O-rutinosida, visenin-2, kaemfero

    Izolacija i sposobnost hvatanja slobodnih radikala cijanidin 3-O-glikozida iz plodova Ribes biebersteinii Berl.

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    The reversed-phase preparative high performance liquid chromatographic purification of the methanol extract of the fruits of Ribes biebersteinii Berl. (Grossulariaceae) afforded five cyanidin glycosides, 3-O-sambubiosyl-5-O-glucosyl cyanidin (1), cyanidin 3-O-sambubioside (2), cyanidin 3-O-glucoside (3), cyanidin 3-O-(2G-xylosyl)-rutinoside (4) and cyanidin 3-O-rutinoside (5). They showed considerable free-radical-scavenging properties in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with the RC50 values of 9.29 × 106, 9.33 × 106, 8.31 × 106, 8.96 × 106 and 9.55 × 106 mol L1, respectively. The structures of these compounds were elucidated by various chemical hydrolyses and spectroscopic means. The total anthocyanin content was 1.9 g per 100 g dried fruits on cyanidin 3-glucoside basis.Pet cijanidin glikozida, 3-O-sambubiozil-5-O-glukozil cijanidin (1), cijanidin 3-O-sambubiozid (2), cijanidin 3-O-glukozid (3), cijanidin 3-O-(2G-ksilozil)-rutinozid (4) i cijanidin 3-O-rutinosid (5) izolirani su iz metanolnog ekstrakta plodova Ribes biebersteinii Berl. (Grossulariaceae) koristeći reverzno-faznu preparativnu tekućinsku kromatografiju visoke učinkovitosti. Cijanidin glikozidi pokazali su sposobnost hvatanja slobodnih radikala u pokusu s 2,2-difenil-1-pikrilhidrazilom (DPPH). Dobivene su sljedeće RC50 vrijednosti: 9,29 × 106, 9,33 × 106, 8,31 × 106, 8,96 × 106, odnosno 9,55 × 106 mol L1. Strukture glikozida određene su kemijskom hidrolizom i spektroskopijom masa. Ukupni sadržaj antocijanina bio je 1,9 g na 100 g suhih plodova preračunato na cijanidin 3-glukozid

    Marine Reserves Shape Seascapes on Scales Visible From Space

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    Marine reserves can effectively restore harvested populations, and ‘mega-reserves’ increasingly protect large tracts of ocean. However, no method exists of monitoring ecological responses at this large scale. Herbivory is a key mechanism structuring ecosystems, and this consumer–resource interaction\u27s strength on coral reefs can indicate ecosystem health. We screened 1372, and measured features of 214, reefs throughout Australia\u27s Great Barrier Reef using high-resolution satellite imagery, combined with remote underwater videography and assays on a subset, to quantify the prevalence, size and potential causes of ‘grazing halos’. Halos are known to be seascape-scale footprints of herbivory and other ecological interactions. Here we show that these halo-like footprints are more prevalent in reserves, particularly older ones (approx. 40 years old), resulting in predictable changes to reef habitat at scales visible from space. While the direct mechanisms for this pattern are relatively clear, the indirect mechanisms remain untested. By combining remote sensing and behavioural ecology, our findings demonstrate that reserves can shape large-scale habitat structure by altering herbivores\u27 functional importance, suggesting that reserves may have greater value in restoring ecosystems than previously appreciated. Additionally, our results show that we can now detect macro-patterns in reef species interactions using freely available satellite imagery. Low-cost, ecosystem-level observation tools will be critical as reserves increase in number and scope; further investigation into whether halos may help seems warranted. Significance statement: Marine reserves are a widely used tool to mitigate fishing impacts on marine ecosystems. Predicting reserves\u27 large-scale effects on habitat structure and ecosystem functioning is a major challenge, however, because these effects unfold over longer and larger scales than most ecological studies. We use a unique approach merging remote sensing and behavioural ecology to detect ecosystem change within reserves in Australia\u27s vast Great Barrier Reef. We find evidence of changes in reefs\u27 algal habitat structure occurring over large spatial (thousands of kilometres) and temporal (40+ years) scales, demonstrating that reserves can alter herbivory and habitat structure in predictable ways. This approach demonstrates that we can now detect aspects of reefs\u27 ecological responses to protection even in remote and inaccessible reefs globally

    Metformin and weight loss in obese women with polycystic ovary syndrome: comparison of doses

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    CONTEXT: Metformin treatment of women with polycystic ovary syndrome (PCOS) is widespread, as determined by studies with diverse patient populations. No comparative examination of weight changes or metabolite responses to different doses has been reported. OBJECTIVE: The aim of this study was to determine whether different doses of metformin (1500 or 2550 mg/d) would have different effects on body weight, circulating hormones, markers of inflammation, and lipid profiles. DESIGN: The study included prospective cohorts randomized to two doses of metformin. SETTING: The study was performed at a university teaching hospital with patients from gynecology/endocrinology clinics. PATIENTS: The patients studied were obese (body mass index, 30 to or =37 kg/m2; n = 41) women with PCOS. INTERVENTION: Patients were randomized to two doses of metformin, and parameters were assessed after 4 and 8 months. MAIN OUTCOME MEASURES: The main outcome measures were changes in body mass, circulating hormones, markers of inflammation, and lipid profiles. Results: Intention to treat analyses showed significant weight loss in both dose groups. Only the obese subgroup showed a dose relationship (1.5 and 3.6 kg in 1500- and 2550-mg groups, respectively; P = 0.04). The morbidly obese group showed similar reductions (3.9 and 3.8 kg) in both groups. Suppression of androstenedione was significant with both metformin doses, but there was no clear dose relationship. Generally, beneficial changes in lipid profiles were not related to dose. CONCLUSION: Weight loss is a feature of protracted metformin therapy in obese women with PCOS, with greater weight reduction potentially achievable with higher doses. Additional studies are required to determine whether other aspects of the disorder may benefit from the higher dose of metformin

    Higher order structure in a short repeat length chromatin.

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